To clarify, why are you so sure that the cost of eliminating trust is greater that the cost of failures to trust?

How sure must one be? Getting rid of the last vestige of anything is never worth the trouble. The amount of resources consumed because people aren't trustworthy is enormous. That's why eliminating trust seems so valuable. PoW overdoes it, though.

I'm less sure about PoS because, frankly, I don't understand its vulnerabilities. I get the impression, though, that PoS is easier to attack, i.e., it does a less complete job of eliminating trust, which may be a good thing. On a more subjective level, I believe, obviously without rigorous evidence, that the kind of resources consumed by crypto - especially human brainpower - are rarer and more valuable than the resources consumed by conventional enforcement. I'm not disparaging cops here, just noting that that no one ever argues that the police force would be better used fighting cancer.

With regards to policy, I don't necessarily agree with centralization being necessary.

Why did you use the word "necessarily?" Do you not see how it make mush of your reply? Indeed, it suffers from the same diminishing returns problem. How sure must you be that I'm right to agree with me? All the way to "necessarily"? This sounds like a nit, but it isn't. I do not believe you could omit the word. What I think you are really saying is that there exist counterarguments, but, in fact, you don't find them persuasive enough to support an opinion you are willing to state as your own. I acknowledged in my comment that central policies are not perfect - how could they be when interests conflict? - but that hardly demonstrates that trying to create a "more perfect" policy isn't the best use of the resources available.

An economy needs a currency that its members can manage, and it turns out that expertise is important. See, for example, Elinor Ostrom's work on managing the commons. The marketplace is a a commons, and the medium that, well, mediates, barter in it must be managed. Only an inflationary currency makes any sense as a currency, and an inflationary currency must expand and contract with the supply of goods it can buy. I'm not aware of any crypto management protocol that can boast of that capability, whereas every centralized currency is designed for precisely that feature.